This invention generally relates to devices used to rejoin a human sternum that has been longitudinally severed, and more particularly relates to such devices that function in a clamping manner to retain the two severed sternum portions in a closed and abutting relationship post-operatively for an extended period of time such that healing of the sternum may occur.
It is often necessary in surgical operations to longitudinally sever the patient's sternum so that the ribs may be spread to provide access to internal organs such as the heart. It is then necessary to secure the bisected sternum halves together for post-operative recovery. Various closure techniques are used to accomplish this task. For example, holes may be drilled into the sternum halves and suture material passed through and tightened to cinch the sternum halves together. Apertured plates may be added to further rigidify the sternum post-operatively, with the suture material being passed through the apertures in the plate and the sternum. Encircling members may be wrapped around the sternum and tightened. Toothed bridging members extending across the cut line may be pressed into the sternum surfaces and/or secured with threaded rods extending between the sternal halves.
Another sternal closure technique involves the use of clamps having hook-like projections or engagement members on both ends, the clamp being positioned laterally relative to the sternal incision with the projections being disposed between adjoining rib pairs. The clamp is then contracted or compressed to shorten the device and force the sternal halves together, the clamp typically comprising two members joined in a telescoping manner. Locking or securing means, either permanent or releasable, maintain the clamp in the contracted configuration.
Examples of such techniques and devices are described in U.S. Pat. No. 3,473,528 to Mishkin et al., U.S. Pat. No. 4,201,215 to Crossett et al., U.S. Pat. No. 4,279,248 to Gabbay, U.S. Pat. No. 4,583,541 to Barry, U.S. Pat. No. 5,139,498 to Astudillo Ley, U.S. Pat. No. 6,051,007 to Hogendijk et al., U.S. Pat. No. 6,217,580 to Levin, U.S. Pat. No. 6,302,899 to Johnson et al., U.S. Pat. No. 6,540,769 to Miller, III, and U.S. Pat. No. 6,712,821 to Gabbay.
Problems occur with these techniques and devices when the sternum is relatively weak due to age, illness, etc., such that the bone material cannot bear the localized stresses imparted by the sutures, bone anchors or clamping devices of the known systems. Closure techniques that require suturing are excessively time consuming. Bracing devices that are not adjustable either in depth or width cannot be properly adapted to correspond to conditions of a particular patient.
It is an object of this invention to provide a sternal closure device having the functionality of a contractible sternal clamp, such that the sternal halves may be quickly and easily forced together and retained in position, but providing greater reinforcement and rigidity to the severed sternum, and which is also effective in circumstances where the sternum is in a weakened condition. It is an object to provide such a sternal closure device wherein longitudinal brace or scaffold members are secured to the sternal halves with the sternal halves retained in a force-spreading, compressive manner, the longitudinal brace members being joined by transversely extending bridging members, the bridging members having locking or securing means, preferably releasable, such that when the longitudinal bridging members and sternal halves are compressed together, the locking or securing means maintain the device in the contracted or tightened configuration with the sternal halves abutting.